Root cause
Past the symptom, to the cause
A Root cause captures the underlying reason an incident or problem occurred, backed by the evidence that supports it. Unlike an action item or a follow-up task, which describes work to be done, a Root cause explains why something broke and is the anchor that prevention work later hangs off of. It differs from an incident summary in that it isolates the single causal factor (or the primary chain of factors) rather than narrating the timeline of what happened.